Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

MangasMangas Solar Expert Posts: 547 ✭✭✭✭
After 10 years, replaced our old central HVAC units with AFUE 97% Furnaces (2) and 3 ton 21 SEER Air Conditioning Compressors (2).

I have been closely watching power consumption but it's too early to tell if I made any system performance gains. The new generation variable speed A/C compressors, air handlers and self modulating furnace technology is really impressive.

Inverters were showing the compressors and air handlers pulling about 14 amps at 63% for each zone. I imagine idling at 25%, they would be pulling maybe 8 amps! I believe this is half what the old units were running. The engineering in these things is just amazing.

Of course the litmus test will be winter furnace performance i.e. propane usage, generator frequency runs and all round pick up in battery storage, if any. Fingers crossed.
Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers

Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,747 admin
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    I have a 95% efficient natural gas furnace in my old house.

    It was pretty much a requirement because the flue run was too long and condensed a bunch of water--Dripped water everywhere and corroded the flue pipe (and probably was not great for a brick chimney.

    Using a plastic pipe as the flue was wonderful. About the only "strange" thing was the fan for the burner air sounded like a (very quiet) vacuum cleaner motor outside where the flue exited.

    Otherwise, an 80% efficient furnace was my choice for my old home... The high price of a 95% efficient unit was not worth the natural gas cost savings over the life of the furnace in our relatively mild winters.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    You're right Bill.

    I can't justify the high price of these 97 AFUE units but I like experimenting with the technologies. As you say, I would have to burn a lot less propane for sure!

    I had to get used to the new 3" PVC "flues" which draw fresh air from the outside. Like yours the furnaces create water like the A/C. I was worried about the drain pipes freezing exiting the house but was told in our climate shouldn't be a problem.

    Those variable speed air handlers and compressors run half the DBA as the old ones. It's the low amps they are pulling which amazes me and the A/C compressors are 220v of course.

    Assuming next year's weather pattern is similar to this one, I am hoping the standby generator runs less than the annual 60-65 hours (2 hour run times) which has been customary. Even 30 times a year (including exercise) isn't bad.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • westbranchwestbranch Solar Expert Posts: 5,163 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    During one of he coldest years recently the exhaust created an ICE column that an ice climber friend wanted to scale (climb) :p, it was ~ 9 feet tall. But he did enjoy the view down from the deck...
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    When it come to anything about my system don't give me something to worry about and I'll worry about it. . .
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    Discovered (after reading the manual) the two new ComfortLink II XL 950 HVAC system controllers have a power management history function.

    Trying to figure out if I can correlate the new system's actual performance with my Outback charge controllers daily power readings for each zone.

    Always a student.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • westbranchwestbranch Solar Expert Posts: 5,163 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    Any additional manual comments on that mgmnt system?

    Logic say to me that they should almost mirror each other if the sample rate is fairly close.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    I went to the "History" menu and it shows (either daily, weekly or monthly) the high and low outside daytime temp, system set temp points and, I believe the percentage the system ran to maintain the indoor indoor temp setting.

    Doesn't give me more but I haven't fully explored it. I did notice an SD card slot in the side of the controllers for future software updates so I'm sure there is more in there or may be coming.

    Tempted to write an email to their engineers to not forget the solar folks and our appetite for power consumption and conservation values.

    Overall, it looks like a pretty sophisticated controller with digital com to and from the HVAC units. So far, I really like it.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • westbranchwestbranch Solar Expert Posts: 5,163 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    Ya, even if they could start by giving you the on/off times of the unit, you could combine that with the charting from the CC and estimate the draw a fair bit more accurately..

    have fun..
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    Good point.

    I bet there is more in there than the "manual" says.

    Plan to look into it with them.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    We had an extended period of inclement summer weather over 4 days with steady A/C draws. Unlike the past, genset wasn't required to help the banks. I figure the AC side of the new system has freed up battery storage, maybe 25%, allowing the panels to keep up with consumption.

    So far, pretty good performance.

    Waiting on winter to see if I can export improvement to the furnace side. This is where storage capacity is most noticeable and the best test.

    Set my goal to reduce total annual genset run time from about 65 hours to 50 hours (net bi-monthly exercise runs). New furnace AFUE (old 85% units to new 97% units) should reduce propane consumption as well.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    After living with it for a few months the new high efficiency HVAC system's power consumption is dramatically less than the previous generation equip.

    I've been monitoring the furnace air handler and propane consumption for over a month and like the AC improvement, I estimate back of the envelope 25%, maybe more improvement in power and propane consumption. Generator hasn't run yet where it probably would have in the past once or twice (extended inclement) and the batteries come up to 100%+ sooner in the AM.

    The variable speed air handlers are showing about at 4 to 5 amp draw on the inverters which is impressive especially, considering the new system has a higher BTU heating and AC rating than the old equipment. Of course, outside temps are only in the 40s' so the system hasn't needed to run at their highest settings yet but overall while the investment in this high efficiency equipment is more money, I think it was worth it.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • BB.BB. Super Moderators, Administrators Posts: 29,747 admin
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    In California, just ran into a new(er) law that just came into effect for us.

    It requires the HVAC ducts to be tested for air leaks... Something like $400-$600 for testing and some more money for repairing any air leaks in exposed ducting (leaking ducts inside walls/ceilings without attics do not have to be repaired).

    Also, from reading the law, they also have to verify refrigerant levels in the compressor system.

    http://hersrater.org/hers.htm

    Another $400-$1,000 or so added to your cost for a new heating system in California (of course, leaking/broken air ducts are not good either). You cannot get a building permit signed off (final inspection) unless you have the test done... Of course, that is just making more heating contractors interested in doing un-permitted installs. Oh well.

    With the new carbon tax coming into effect in January (last I heard)--We are going to approach Alaska+Hawaii in cost of living, I fear.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    Unreal Bill.

    A lot of hot air leaking out of the legislative duct system. Are they too going to be tested? Doubt it.

    There is no end to what the bureaucrats will do to create the illusion of energy efficiency. Money has no meaning when over 40% of what the public sector spends is borrowed. We are accountable to a different economic model.

    Now a California carbon tax. Wonder what the rates will end up being over your way?
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • westbranchwestbranch Solar Expert Posts: 5,163 ✭✭✭✭
    Re: Installing AFUE 97% Furnaces & 21 SEER A/C Compressors

    It's (taping all joins in the piping) been standard on NEW construction for several years up here (BC), BUT a retrofit when no changes are being made to the house?? How did that thinking get started???
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    For those who follow this stuff.

    I just serviced my Cummins Onan 20 kw Propane 1,800 rpm Genset and noted that it only ran a total of 2.5 hours for the past nine months since I installed the two Trane high efficiency AC Units & Compressors, Propane Furnaces & Air handlers. The genset's 2.5 hours of run time corresponds to only the 15 minute monthly exercise schedule over the past nine months.

    Pretty good performance despite frequent inclement weather periods. Validated the extremely low energy consumption of the higher efficiency HVAC system which coupled with replacing higher energy washer, dryer, fridges and TVs during the year has resulted in zero genset usage since November 2014. The genset used to run 60-80 hours a year with the old equipment and appliances.

    Several months ago, I also replaced my four 10 year old Xantrex SW 5548 Inverters with four Schneider XW5548 NA Inverters (two stacked sets/2 each ), two MPPT 80-600 Schneider charge controllers, two Xanbus control modules and two control panels.


    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Propane supplier just left topping off our tanks.

    Despite the mild winter this year we estimated  replacing the HVAC system and major appliances with high efficiency units has cut our annual propane consumption by about 30-35 percent.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • m151m151 Registered Users Posts: 25 ✭✭
    Mangas,just curious? why did you replace your SW's?
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    edited November 2015 #19
    The old 5548s' were 10 years old, mother boards and transformers are getting scarce. The new XW plus inverters seem to work better but were complicated to set up and I had a very experienced contractor doing it.

    Because of our remote location, I don't like to run the clock out on hardware which can be stressful.  I'm just built that way.  The old Trace units were simply bullet proof.  The Schneider equipment has some very big shoes to fill!
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    For on grid folks in California the cost of propane for heating (building or water) is comparable to the cost of using grid power with a heat pump for the same heating job. When the A/C function is also needed, the added cost of the heat pump equipment for the added heating function is favorable too.
    It is only because off grid PV or generator power costs so much more than grid power and PV energy is limited that propane becomes a good alternative.
    SMA SB 3000, old BP panels.
Sign In or Register to comment.